A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using

The wettability of a surface by a liquid depends primarily on

The molar specific heats of an ideal gas at constant pressure and volume are denoted by C_p and C_v, respectively. If  $$\gamma $$ = $${{{C_p}} \over {{C_v}}}$$ and R is the universal gas constant, then C_v is equal to

The following four wires are made of the same material. Which of these will have the largest extension when the same tension is applied?